Happy Birthday
by CharlieSwagron
Summary: It's Kate's birthday and she's had a horrible day. The case is going badly, her friends couldn't hang out, and to make matters worse, Castle's out on a book tour. What happens when she comes home at the end of the day and a certain someone shows up to surprise her?


**A/N: I wrote this because of a prompt in the tags I saw attached to a Castle post on tumblr. Here's the link (just take out the spaces): onceuponacaskett . tumblr post / 90711425821 / rickmanpartscastle – one – day – someone – is – going - to**

The door to the loft opened and in entered an exhausted detective. Kate was feeling absolutely miserable. The case she and the boys had been working on hadn't progressed anywhere in the last three days; no suspects, no new information, and no leads whatsoever. They'd been scouring everywhere, trying to find _something_ that would further the case along, but nothing was coming up. If they didn't discover anything new tomorrow, then Gates was threatening to shelve the case and have them move on.

Kate hated doing that: filing away homicides under the cold case stack. She knew better than most how the family of the victim felt when these things happened. They would feel confused, disappointed, upset, and more often than not they would be angry that New York's finest had been unable to solve their loved one's murder.

And they had a right to be, she thought to herself. She knew firsthand how helpless and frustrated you could feel as you received no closure, no justice to be found for your loved one.

To make matters worse, Castle wasn't even here to lend a hand or to whisper words of comfort to her as she sulked. He was on his latest book tour, promoting the latest Nikki Heat novel. He hadn't wanted to go, but Paula—and Kate—hadn't taken no for an answer. Kate had encouraged him to go and interact with his adoring fans considering he'd skipped out on the last tour so that he and his new wife could enjoy their honeymoon together.

Kate sighed. She desperately missed her husband. She hadn't been able to talk to him all day and it was getting to her. The emptiness of the loft was only magnified as she dropped her keys on the counter and stored her gun away, both actions echoing loudly throughout her home.

Martha and Alexis were away at the Hamptons, enjoying the gorgeous mid-fall weather in the beachfront house. Ryan had left as soon as the clock hit six to hurry home to Jenny and his beautiful daughter. Esposito and Lanie were still trying to get their act together and were out on a date. Kate was truly alone tonight.

To top it all off, today was her birthday. Her friends had all wished her a happy birthday and had given her their presents earlier that day, knowing full well that they'd be unable to spend time with her later and celebrate. She'd been grateful for their acknowledgments of her birthday, but the one person she'd been waiting to hear from all day, hadn't even tried to contact her. Not even a single text sent.

A part of her—the paranoid detective part—was worried that something had happened to Castle; it was completely unlike him to forget her birthday. Ever since he'd discovered the date, he'd made it his mission every year to go out of his way to make it a very special day for her. This year, however, he wasn't here and Kate was lonely, the regret for sending Castle on his book tour settling in.

Making her way to their bedroom, she stripped off her shoes, letting them fall to the ground as she flopped on her back onto the bed. Curling on her side, she grabbed her husband's pillow that hadn't been used in three weeks and clutched it in her arms. It still smelled like him. She buried her face into the pillow and inhaled his scent, letting it wash over her as she felt a couple tears slip down her cheeks.

She missed him. She missed him so much that her heart was starting to ache. She wanted him right there beside her, holding her in his strong arms, his chin resting on the top of her head. They hadn't been apart for longer than a day since her stint as a federal agent in D.C. and she hadn't realized that three weeks without Castle would hurt this much. If she had known, she would've done everything in her power to have made him stay. Especially after she'd discovered something a few days ago.

A knock on the front door brought Kate out of her miserable thoughts. Wiping the tears from her eyes, she curiously wondered who would be knocking on her door at this time of night. When she opened the door, she gasped.

"Hey," Castle said softly, almost shyly as he clutched flowers in one hand at his side. In his other hand, he held a small gift bag. "Happy Birthd—"

Before he could utter another syllable, Kate had taken a hold of the front of his shirt in one tight fist and yanked him to her, the momentum of his body carrying them farther into the loft. Castle kicked the door shut behind him and let the bag and flowers drift to the floor.

The second Kate's mouth made contact with her husband's she nearly cried with relief. He was here. He was home. Her arms wound tightly around Castle's neck, pressing his lips harder onto hers, trying to get closer and lose herself within him. The strong arms that Kate had wanted holding her just a few short minutes ago, wrapped around her waist and lifted her off the ground.

As soon as she felt her feet in mid-air, Kate wrapped her legs around him. He walked them both over to the couch where he sat down with her in his lap. Their mouths finally disconnected as they pressed their foreheads together, neither willing to break apart.

"You here," she whispered.

"I'm here," he echoed.

"I thought your book tour wasn't supposed to end until next week."

He shrugged. "I decided to cancel the rest of it. Three weeks away from you is too long. Next time, you're coming with me whether I have to drag you along or not."

"I'm sure that won't be a problem." Burying her face in the crook of his neck, she added, "I've missed you too much for you to leave me alone like this again."

Castle smirked. "Did the great and fearless Katherine Beckett just admit to missing my presence?"

Flicking him on the ear, she said, "Katherine Beckett admits to nothing. Katherine _Castle_, however, might've just confessed to it."

He felt her smile into his neck and held her tighter. "You know, you made me drop your present and flowers. I kind of need to go get them."

She was clinging to him like a koala and she knew it. Somewhere in the back of her mind she registered the fact that she should be at least slightly embarrassed with her behavior, but at the moment, Kate couldn't really bring herself to care. Sighing, she released him and crawled out of his lap to allow him to fetch her gift.

He placed the flowers on the coffee table in front of the couch before handing her the bag. "Open it," he instructed.

She pulled out a long, blue velvet box. Prying open the lid, her breath hitched at what lay inside.

"I know it's nothing really fancy and it's probably cliché to get someone on their birthday, but I figured I could just get you something bigger or better for Christmas or for our first anniversary or—"

"Castle," she interrupted his rambling. He only did that when he was nervous. Examining the necklace he'd gotten her, she fell in love with it. Attached to a long silver chain, the letter "K" sat at the bottom, decorated in little topazes, her birthstone. He was right: it wasn't fancy and it _was_ a little cliché to give as a gift, but it was a simple piece of jewelry that she'd be able to wear at work underneath her shirt.

She'd long since stopped wearing her engagement ring around her neck after it had accidentally fallen off its chain one day. She hadn't wanted to take any chances of losing it so now, the ring stayed in her small jewelry box, only to be worn when she was off-duty. Castle had given her a simple, plain band of platinum during their wedding and that was what she wore at work to show others that she was happily married.

"It's beautiful," Kate told him. "You know I don't need flashy or expensive things."

"I know," he replied. "I'm just used to spoiling you and _getting_ you those expensive things so I guess this seemed like it was very dulled down in comparison."

"Yes, but how many times do I tell you not to buy me those expensive gifts yet you do it anyway?"

"Point taken," he conceded. "You really like it?"

His partner nodded. "I love it, Castle." She leaned in for a kiss which he happily obliged. She could feel his grin against her lips and chuckled.

Pulling back, she placed the velvet box and the now empty gift bag on the coffee table, turning back to him with an anxious expression.

"What's wrong?" Castle asked her, worry on his face.

"Nothing's wrong," she assured him. "But, uh…there's something I need to tell you."

The writer frowned, his wild imagination already jumping to horrible conclusions despite the fact that she said nothing was wrong. His frown only deepened when Kate reached over and took his hands in hers.

"A few days ago, I found out something about me that I need to share with you. It's actually been really hard to keep it to myself until now," she began.

"Kate, are you sick?" he asked. "Please, tell me you aren't, but if you are then—"

"Castle, I'm not sick," she told him. "Although for the next several weeks I may be I may be vomiting quite often throughout the day."

Her husband looked completely lost. "Kate, I don't understand. What's going on?"

She bit her lip and took a deep breath, a smile blooming across her face. "Castle…I'm pregnant."

It was almost comical how sudden Castle's expression changed. If Kate hadn't been nervously waiting for his response, she would've laughed.

"You're…pregnant?" he stuttered out. At her nod, he looked down at her stomach in awe. Gently placing his hand on her still flat belly, an elated grin overtook his face. "Why didn't you tell me before now?"

"I wanted to wait until I saw you in person," she told him, her bottom lip still captured between her teeth.

"Jesus, Kate, we're having a baby!" he exclaimed. In his excitement, he nearly tackled his wife, pushing her onto her back on the couch. He hovered over her, supporting himself on one arm, and peppered her face and neck with kisses.

Releasing a very un-Kate-like giggle, she cupped his cheeks with her palms, forcing him to look at her. They wore matching grins that neither could get rid of. Kate turned on her side and gestured for Castle to lay down behind her, his arm wrapped around her waist while his hand remained on her stomach; the stomach that now held the growing life they had created.

As Kate rested her hand on top of her husbands and laced their fingers together, Castle said, "Even though it's your birthday and not mine, I can't help but feel like this is the greatest present ever. _Way_ better than mine."

"I know what you mean, Castle," she replied.

"Happy Birthday, Kate." He tilted his head down to brush a kiss against her forehead.

After a few minutes of both just reveling in each other's presence as well as the company of the new third party taking residence in her stomach, Kate broke the silence.

"So when do I get that birthday/welcome home/celebratory sex?"

The second the words were out of her mouth, Castle hopped up off the couch and grabbed her hand. "God, I thought you'd never ask!" Her laughter could be heard echoing off the walls of the loft as he practically dragged her into their room and slammed the door shut.

**A/N: It almost killed me to write in the pregnancy just because it seemed so cliché and overused, but then I thought why the hell not? It's a cliché for a reason: 'cause it works. I hope you guys enjoyed this a lot and thank you for taking the time out of your schedules to read it.**


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